This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Conventional two-photon fluorescent microscopy technique allows tissue imaging only at depths less than 1mm. The project goal is to develope a practical devise that will be capable of fluorescent imaging in tissue at depths of few mm and deeper. The novel proposed detection system utilized in the project possesses superior light collection efficiency and sensitivity that will allow imaging in deep layers of turbid media.